/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the  "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id$
 */
package wx.xml.xalan.xalan.transformer;

import java.util.Vector;

import wx.xml.xalan.xalan.templates.ElemTemplateElement;
import wx.xml.xalan.xml.utils.PrefixResolver;
import wx.xml.xalan.xml.utils.QName;
import wx.xml.xalan.xml.utils.XMLString;
import wx.xml.xalan.xpath.XPathContext;
import wx.xml.xalan.xpath.objects.XNodeSet;

/**
 * This class manages the key tables.
 */
public class KeyManager {

    /**
     * Table of tables of element keys.
     *
     * @see wx.xml.xalan.xalan.transformer.KeyTable
     */
    private transient Vector m_key_tables = null;

    /**
     * Given a valid element key, return the corresponding node list.
     *
     * @param xctxt     The XPath runtime state
     * @param doc       The document node
     * @param name      The key element name
     * @param ref       The key value we're looking for
     * @param nscontext The prefix resolver for the execution context
     * @return A nodelist of nodes mathing the given key
     * @throws javax.xml.transform.TransformerException
     */
    public XNodeSet getNodeSetDTMByKey(
        XPathContext xctxt, int doc, QName name, XMLString ref, PrefixResolver nscontext)
        throws javax.xml.transform.TransformerException {

        XNodeSet            nl       = null;
        ElemTemplateElement template = (ElemTemplateElement) nscontext;  // yuck -sb

        if ((null != template)
            && null != template.getStylesheetRoot().getKeysComposed()) {
            boolean foundDoc = false;

            if (null == m_key_tables) {
                m_key_tables = new Vector(4);
            } else {
                int nKeyTables = m_key_tables.size();

                for (int i = 0; i < nKeyTables; i++) {
                    KeyTable kt = (KeyTable) m_key_tables.elementAt(i);

                    if (kt.getKeyTableName().equals(name) && doc == kt.getDocKey()) {
                        nl = kt.getNodeSetDTMByKey(name, ref);

                        if (nl != null) {
                            foundDoc = true;

                            break;
                        }
                    }
                }
            }

            if ((null == nl) && !foundDoc /* && m_needToBuildKeysTable */) {
                KeyTable kt =
                    new KeyTable(doc, nscontext, name,
                        template.getStylesheetRoot().getKeysComposed(),
                        xctxt);

                m_key_tables.addElement(kt);

                if (doc == kt.getDocKey()) {
                    foundDoc = true;
                    nl = kt.getNodeSetDTMByKey(name, ref);
                }
            }
        }

        return nl;
    }
}
